Lawn mower



D. WENHAM LAWN MowER` March 3, 1931.

Filed-feb. 21, 1929 r Patented Mar. 3, 1931 'PATENT OFFICE DOUGLAS WENIIAM, OF HAMILTON, NEW ZEALAND, ASSIGNOR T WENMUR BLADES LIMITED, 0F HAMILTON, NEW ZEALAND, A GOMPANY OF NEW ZEALAND i LAWN MOWER Application led February l21, 1929, Serial No. 341,579, and in New Zealand April 3, 1928.

This invention has been devised with the i object of providing improvements in the ordimower showing such engage the nary type of lawn mower, by means of which there is provided an improved cutting edge for the cutter blade that may be removed from time to time as required and that has a resilient springy effect in its contact with the rotating knives of the machine, and by means of which also, the tension of the said cutter blade upon the rotating knives may be more readily -adjusted than is possible with the present means provided for this purpose.

' In fully 'describing the invention, reference willbe made to the accompanying drawings, in which Figure l is a cross section through a lawn portions of the machine with which this invention is concerned and looking to one end thereof.

Figure 2 is a similar view but looking to the other end of the machine.

Figure 3 is an end elevation of the knife carrier and knife mounted thereon.

JIFigure 4 is a cross sectionalelevation thereo Figure 5 is a plan of one end of the knife carrier and knife.

Figure 6 is a front elevation thereof.

The invention is concerned with the known construction of mower in which the knife blade is screwed, or otherwise secured, to a carrier bar A extending across between the side members B of the mower frame, and such carrierbar is attached to or formed in one with bracket members G-G at its ends, each of which brackets is mounted upon the adjacent frame side member by a trunnion pin that allows of the carrier being tilted to cause the knife blade to be adjusted in relation to the rotating cutter knives. This adjustment hitherto has generally been effected by forming each bracket with extensions c extending forwards and rearwards of the trunnion, and in providing set screws which pass down through lugs E on the frame member B and tops of these bracket extensions c so that by the relative adjustments of these set screws, the brackets are tilted and held in the adjusted positions. This manner of adjustment thus entails the manipulation of fourV set screws and is therefore slow in accomplishment. j

In the present invention the adjustment is simpliiied and is effected by the manipulation of a single hand screw.` Conveniently, this is accomplished `by providing; that the brackets shall be tilted together,` through theirl integral connection withl the carrier bar A, and by the operation of a hand screw F passing down through aA lug Ei and bearing upon the: rear extension c of onefbracket, in opposition to a springy` resilient force, in compression, bearing upon the fonwand extension. c of the other bracket, or ofl both brackets, if so'desired.` lSuch spring action -is obtained: by arranging a` spring G between the forward lug E of the frame member B and the extension 0': ofithe bracket, such springI being maintainedrin place by means of a set screw Gripassing down through` the said lug. 0n alternatively, the, hand screw may be arranged to` pass down througra frame part and to bear upon a rearward lever extension of the carrier positioned. at about midway in its length. The. hand screw may rhave means combined therewith for' locking it' fromuturning.,

Or, as a further alternative,the positions of the spring G- or other resilient member and the. hand screw F relatively'to theA back and. front of the carrierl may bereversed.` Instead-of the hand screw beingused, a wedge; may be provided to bearbetween the bracket extension and the, frame lugt and; by being-moved in, or.` out to provide fonthe adjustment desired. This wedge is con'- trolled' in its movements by a levery attached to, the frame andhavingmeans for locking itfinany adjustedposition. l The -knife in this invention is; formed by a thin strip H of flexible steel: andthis is held upon` the carrier bar by haVi-ngiits inner edge gripped withina holder bar attachedto.` the said carrier` barso4 that the outer edge; of the knife Vproj ects forwardly andfis'engaged bytherotating knives inthe usualway. The Vcarrier bar isset so that the knifev is Yengaged by the rotatingl cutterknives lwith a close springy engagement and a resiliency in its action that will ensurej of anfeifectivecut ff' l1,795,102Y

being obtained and will also always mainsaid holder having a slot extending along its tain a sharp cutting edge. front edge and a ledge projecting out beneath The said holder bar is so formed as'to prosaid slot, said ledge having an upwardly vide for .the back edge of the knife strip be turned liange on its front edge and an over- 5 ing gripped and for it beingrernoved and hanging lug on one Vof itsends.

replacedrat will. This is given effect to by In testimony whereof, I affix my slgnature.

' Y DOUGLAS WENI-IAM.

making the-'bar of two parts,"a lower plate J that is aiiiXedby screwing or otherwise, tothe bottom of the carrier bar and has its forward edge projecting a distance forwardv v Y 1 lyof this bar, and vanupper strip K that is c 5 secured toextendalongthe top surface of ,f f the plate J as by being riveted thereto. This i strip Klis` madefof less width than the plate J andis so shaped at its forward portion as'to form with the plate, the slot Mextending along the full length of the bar and into'which theknife back edge'is fitted and gripped so that its'forward edge overhangs l 'T20 the plate Jy the'manner before described. Y Y

-The forward topedge of the plate J is l Y e 85 preferably made with a slight ridge j so that f .Y -the knife H is given an upward set at its front edge that will increase its springiness L'25 in vcontact withthe rotating cutter of the .Y f Y machine. The knife is lmaintained from I 90 rcurving upwardby means of an overhanging lug N- `formed on one end of the plate JY and beneath which that end of the knife passes. This lug is formed on the end with @gagein their operation. A e In some cases the holder bar itself may be 1 t given a resilient cushioning elfect'inits relation to the cutter knives,byinserting between Y y j e 1 therear edge .of the plate J and 'the carrier f Y Y Y Y 100 bar, a strip of. resilient material such ras rubber.v` Y

yIvclaim:-. L. Y i

.1.V In a lawnfmower having a knife-carry- Y ing bar extending betweenits side-frame f y 1 105 members and pivoted thereto and having a Y i Y knife-holder secured to extend along said bar,

said holder having a slot extending along its 45 fronted efand aledge projecting outside said i Y Y Y v Y Y l slot,`saidg ledge having means on its front edge f i f no forgivingtheknife an upward set thereat to s v v y therebyincre'ase'the springiness'of said knife when contacting therotary cutter. A i' '2. In aflawn-mower having a knife-carry- Y ,i

ing bar extending between its side-frame 'f f' A U5 members and pivoted thereto and 'having a i knife-holder secured Vto extend along said bar, said holder having a slot extending along its Y front edge and a ledge projecting outside said slot, said ledge having means onts front edge for giving the knife an upward set thereat to thereby increase the springiness of said knife ,Y l i when contacting the rotary cutter, and said r Y Y p Y Y @D ledge having means at one end thereof for A 125 Preventing the knife from curving upwardly. A

ing bar; extending; between its rside frame y members'and pivoted thereto andv having a x f @D knife-holdersecuredtoextend alongsaid bar, f @18o .which the rotating cutterwknives first en- 5 

